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Online Catalogue last updated 17th of September 2023

The Tinker tool & Cutter Griding Jig plans

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Let's look at the TINKER Tool and Cutter Grinding Jig, and some of the questions you are likely to have about it:


The TINKER Tool & Cutter Grinding Jig was invented and patented in the early 1970's by Norman W. Tinker of Nottingham, England. He had been developing and refining the design for more than 10 years. It is a tested, proven and practical design, easy to make and easy to use.

Guy Lautard writes:

I ordered a set of drawings from Mr. Tinker about 1982 or so, and built two, in collaboration with friend and fellow home shop machinist Roy Bickerstaffe. We were impressed with its simplicity and its utility for guys like us, so much so that I later arranged to be the North American agent for the design.

What is the TINKER?

The TINKER is the answer to a maiden's prayers, particularly if she happens to be a hsm, gunsmith, machine shop owner, vocational school teacher, etc.

The TINKER is about as big as a basketball. It teams up with any ordinary bench grinder to provide the small shop owner with a highly versatile tool and cutter grinding (T&CG) capability. All you need, then, is your bench grinder, an appropriate grinding wheel for same, the TINKER, a common base, and a space about 2 ft. square. You don't even need a cup wheel, although one can be used.

What sort of a Grinding Wheel will I need?

A standard white Aluminum Oxide wheel of 60 grit is fine. I use a half inch wide, 6" dia. straight wheel from Norton. The abrasive spec on it is 32A60K5VBE, correct for high speed steel and hardened carbon tool steel. You can use a cup or dish wheel if you want to, but it is not necessary to do so for the normal run of work.

Is it Hard to Build?

No. The TINKER utilizes two identical castings, one machined just slightly different from the other. Most of the machining throughout the TINKER is not to critical limits. The only parts of the whole job that must be done to tight limits are the Tool holder, the Tool holder Guide Block (a 1-1/2" sq. x 3" long block that the Tool holder passes through), and the hole in the round boss on each casting.

What Sort of Equipment do I need to Build my TINKER?

With the exception of machining the two castings, the TINKER could probably be built entirely on a 6" swing lathe. To machine the castings, you will require the use of a larger lathe, or a shaper, or a milling machine. The castings are not hard to machine, but do require access to suitable equipment - if not at home, then perhaps through a friend, or at night school, or at a local machine shop. No tricky setups or difficult operations are involved in machining the castings.

The Tool holder is 7/8" x 7-1/2" long. To get that #2 MT socket in there right requires not only a #2 MT reamer, but also a lathe with a spindle bore greater than 7/8", and/or a good-sized 4-jaw chuck; the proper performance of the finished TINKER depends upon virtually perfect concentricity between the O.D. of the Tool holder and the #2MT socket in its nose. This is one of 3 similarly demanding tasks noted above that are involved in the building of a TINKER. The rest is pretty easy work.

The TINKER is not a complex item to build, nor will it take you a great deal of time. Obviously building time will vary from one maker to the next, but I think that any hsm who puts his mind to it could have a basic TINKER in service within a month of receiving the drawings, working on it in his spare time.

Anyone who builds himself a TINKER and devotes some time to becoming proficient in its use will find his efforts well rewarded. (T&C grinding is a branch of the machinist's trade, and as such, demands some skill development - you do not buy the expertise with the machine, whether it be a TINKER or a Cincinnati!)


The TINKER is not intended to rival a dedicated, purpose-built T&C Grinder by such legendary builders as Norton, K.O. Lee, Cincinnati, Oliver, or Brown & Sharpe. Nor does it have the cost, weight, and bulk of a "real" tool and cutter grinder - a significant advantage for the guy with a shop 12 feet square, like mine. But with it you can accurately sharpen cutters that you can't do freehand.

What will it do?

The basic TINKER T&C Grinding Jig is terrific for sharpening the end of end mills and slot drills. This operation is easy to learn to do well, and can be done very quickly. In my opinion, even if all you want to do with it is to sharpen end mills and slot drills, this capability alone would justify building a TINKER. Set-up time is minimal, and once the TINKER is set for this operation, you need only change the Tool holder collet to suit the shank diameter of the cutter you want to sharpen at the moment. Slot drills I have sharpened on my TINKER take no back seat to factory new cutters - they cut like a razor on both flutes, and they leave an impeccable finish on the work.

As you probably know, the end cutting teeth of end mills and slot drills are sharpened with a "fish tail," or slight dishing toward the center. The TINKER does this automatically, without any "setting up" beyond correct assembly: one bolt in the right one of 2 holes - simplicity itself. For those who don't know why such cutters are sharpened thus, it is fully explained in the TINKER User Instructions, which come with the working drawings and instructions.

The basic TINKER will also sharpen the side cutting teeth of end mills, slot drills, and similar cutters. This requires a bit of skill development, but is not difficult: just don't expect (although you may get) perfect results the first time.

The basic TINKER will also let you sharpen the following cutters: slab mills, tee slot cutters, counterbores, countersinks, woodruff cutters, and some other cutters.

The basic TINKER, with simple adapters which you can make as needed, will also sharpen circular wood saws, slitting saws, and side and face milling cutters. Norman Tinker says so - I've never tried this type of work because I don't own any side and face milling cutters. But if he says it, you can believe it, and if you want to, your TINKER will let you do it. The capacity limit for wood saw blades will depend on the set-up used. More than one way is possible, but suffice it to say that sharpening a 9" saw blade would be routine, and a 24" blade (that is not a misprint) would be entirely possible, with a bit of finagling.

Why do you say The TINKER is easy to set up?

The TINKER is set to produce any desired relief angle by offsetting the Toolhead above or below the grinder wheel center height. This is done via a simple-to-make, simple-to-use Setting Gage (just a piece of 1/4" CRS with some graduations cut in it) which permits direct setting of relief angles for right and left handed, straight and spiral toothed cutters. There is no need to refer to tables. No calculations are required. Once set to produce a given relief angle, the TINKER will produce that angle on a cutter of any diameter. This means that if you want to sharpen several end mills of different diameters, one after the other, you can do so without further adjustment.

Another useful feature of the TINKER is that the Toothrest Finger is attached to the Toolhead. Thus, when the Toolhead is raised or lowered to set up a desired relief angle, the Toothrest Finger moves with it, undisturbed, and remains set to the correct height. The whole operation is completed in a matter of seconds. A separate gage (very simple, takes about 10 minutes to make), allows you to set the Toothrest Finger EXACTLY on Tool holder center height in about 5 seconds flat.

How are Cutters Held?

Cutter shanks are held in a sliding Tool holder, the end of which carries a #2 MT socket. You can make yours different if you want, but that's what the drawings show, and what we recommend.

A set of #2MT bushings which you can make for yourself will take tool shanks up to 5/8", or factory-made #2MT collets can be bought in any size desired up to 1/2". I made my TINKER's Tool holder nose to take Myford #2MT collets, because I already owned several of these, in all the right sizes, for my Myford lathe. (#2MT collets of other makes besides Myford can be had, and will do fine. See note at end of price list.) The drawings include details for a nose cap dimensioned to suit Myford collets, exactly as mine is made. My friend Roy B. made his (and you can too) per Tinker's original design, using the solid steel bushing type; these are also fully detailed in the drawings.

What about Cutters with Larger Shanks?

The drawings give broad details of a larger Tool holder capable of taking cutter shanks up to 1". Some builders have made their TINKER with an R8 socket, thus enabling them to use R8 collets from their milling machine. (More ideas re this are given in the one-time TINKER Newsletter, which you get with the TINKER drawings.)

Will the TINKER will sharpen other cutters, too

The Lathe Tool Bit Grinding Attachment permits grinding lathe tool bits, e.g. small parting tools and screwcutting toolbits for 60 degree Vee, Acme, and other thread forms, where known angles have to be produced with accuracy. Twist drills from about 3/4" on down can also be sharpened with this accessory.

With the addition of a small pin chuck, e.g. the Eclipse #160 or Starrett #240 pin vise, small drills from 1/8" down to #80 can be sharpened direct from the main Tool holder. Personally, I'd just as soon not have to prove that the TINKER will sharpen a #80 drill, but with the right stone, and care, there is no reason to think it would not.

Substitute a good 0-3/8" drill chuck on a 3/8" or 1/2" straight shank, and you can do drills up to 3/8", again direct from the Tool holder, probably about as good as a skilled machinist can do them offhand. The Newsletter gives yet another method of sharpening drills up to 1/2", which N.W. Tinker discovered after I issued my TINKER drawings in the Summer of '85.

NOTE: A certain amount of operator skill and technique must be developed for consistently good drill sharpening results. It is only fair to say that drill grinding is not the TINKER's strongest point, and if you just wanted a drill grinding machine, a purpose-built unit such as the Darex Drill Doctor would be a better choice than the TINKER.

Add the simple Cam Plate and Follower Accessory and you have a method of tap grinding! I've only done a few taps this way, holding them in a 3/8" drill chuck. It works fine, and is not difficult, but it does take some care in setting up.

Norman Tinker also showed a dedicated set of Tap and Die Holders in his drawings. These I did not make, but they are shown in my drawings. (Obviously, to grind a threading die, a small mounted point will be required.)

The Radius Grinding Accessory will let you grind lathe toolbits to known convex and concave radii. Its use takes some care, but it does the job. If you need to grind a radius of say 0.175", it'll do it, or close enough to keep most of us happy, anyway. (NOTE: This item could also be modified and built as an entirely separate accessory for your bench grinder.)

The Reamer Sharpening Attachment replaces the entire Guide-Toolholder-Toothrest Bracket assembly. This attachment is really a set of dead centers of 5/8" center height, in which can be mounted any cutting tool with center holes at each end, such as a reamer, etc. The between-centers capacity as drawn is about 9.5"; this could be increased somewhat at the builder's option.

There are also drawings for a Wheel Dressing Tool, which can be used from the Tool holder for accurate dressing of the grinding wheel, and miscellaneous minor items.

How do I set up my TINKER once I get it Built?

The TINKER is set up on a flat base beside your bench grinder. This base can be a 1/2" steel plate, or a sheet of good plywood overlaid with sheet metal. Typically the base is 12" x 18". The grinder sits on the left, the TINKER on the right. Several holes are provided in the base to permit bolting the TINKER down (one bolt) wherever a particular operation calls for it to be placed relative to the grinder.


The drawings are printed on standard 8-1/2 x 11" paper, with a sufficient margin on the left hand side so that if you want, you can put them in a 3-ring binder for easy reference. Explanatory notes appear right on the drawing they apply to, so the info you need is right where it should be - you don't have to flip back and forth from text to drawing. These notes will save you hours of time through not having to try to read the designer's mind.

If you follow my notes, you will also not need to waste your time thinking up shortcuts: they're already built right into the drawings. (No doubt you'll think up shortcuts of your own, too.) You will also avoid having to scrap and re-make parts, and/or having to re-draw some part or parts to find out where to put something, or stand around in the middle of the shop wondering what to do next! Working from a set of drawings and notes like this is somewhat like the two of us talking face to face, me having just made my TINKER, and you now working on yours.

Code No. 012019, $85.00

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